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By Scott Ellenbecker

Soon New York City will have a new train station. A tunnel project is under construction to extend Line 7 to a new station that is located near the Jacob K. Javits Con-vention Center. This is also part of the Hudson Yards redevelopment project that is intended to aid redevelop-ment of the west side of Midtown Manhattan around the Long Island Railroad?s Caemmerer Railyard. The station, or ?cavern? as it?s called by those excavating it, will be the portal for that growth. In the city, public transportation means high-rise residential proper-ties will have better access to the business district, and those outside the area will have greater access to event facilities ? two factors that are critical for development investment.

Jan 3, 2010

New developments in the pipe conveyor and belt are advanced to address the growth in the capacity, length and complexity of pipe conveyor systems. Improved belt construction can offer better stability during horizontal curves and resistance to twist. Low rolling resistance rubber compound can significantly lower the power consumption and belt tension, producing capital and operation cost savings. Dynamic analysis, when used to analyze the conveyor?s starting and stopping behavior, can improve the design and reliability of long overland pipe conveyor systems. For these three aspects, technical backgrounds and field installations as examples are discussed in this paper.

Jan 1, 2012

St. Peter sandstone is very different from the minerals and rocks that have been studied extensively in mining. On the one hand, it is brittle as characterized by an unusually high friction angle and steeply curved failure envelopes. On the other hand, it is friable, possessing extremely low, and in most cases zero cohesion. The scarcity of the ground control techniques for this particular mining environment has created many difficulties for the mine operators. In order to resolve these problems, the geotechnical properties of the St. Peter sandstones were investigated through a comprehensive research program, which included uniaxial test, triaxial test, porosity test, thin section, X-ray diffraction (XRD), and scanning electron microscope (SEM). The specimens used for the uniaxial and triaxial tests were specially prepared because of the highly friable nature of the St. Peter sandstone. Thin section, XRD and SEM were utilized to examine the effect of the microstructure of the St. Peter sandstones on its strength characteristics.

Feb 27, 2013

By M. M. Poulton

Universities are not immune from the large number of retirements facing the mining industry. Department heads anticipate that we will need to replace all of the senior mining engineering faculty in the U.S. by 2020. Long term studies of Ph.D. completion times and success rates indicate that in Engineering disciplines in the U.S., the ten year completion rate is 65% at best and the four year completion rate is less than 8%. We do not have accurate data on completion rates and times for mining or metallurgical engineering Ph.D. students in the U.S. but students self-report their expected completion times are around 4 years. National data on doctoral students indicate that younger, full time students with sufficient financial support have a higher probability of success in completing their degrees in a timely manner. Students in Eastern U.S. mining engineering programs are on average 32 years old, 85% are full time, and the gap between support and cost of attendance is $5,000 per year. Students in Western U.S. programs are on average 38 years old, 78% are full time, and the financial gap is $8,483. Further, it appears that domestic graduate students are not very geographically mobile. The current demand for new faculty is higher in Western programs but the longer term retirements are higher in Eastern programs. While all Ph.D. students who responded to the 2010 survey indicated an interest in a faculty position at some point in their careers, very few were applying for the open positions. Over the past 35 years for which data could be obtained, the maximum number of Ph.D. students enrolled in mining engineering in the U.S. is 115 with a maximum of 27 degrees granted in one year. On average 89 students are enrolled in doctoral programs in mining engineering in the U.S. with average degree production of 15 Ph.D.s per year.

Jan 1, 2012

By J. F. Stenebråten, W. P. Johnson, D. R. Brosnahan

Carbonaceous material (CM) from ores of varying preg-robbing activity from Barrick Goldstrike Mines Inc. (BGMI), Nevada, was characterized in terms of its functional group content, hydrocarbon content, elemental composition, and humic acid content. FT-IR analyses showed neither the presence of hydrocarbons nor of carboxylic, phenolic, or sulfhydrol functionalities. FT-IR bands present included C=C stretching in aromatic rings and C-O-C stretching, indicating presence of oxygen as ether linkages in the carbon matrix. Calculated atomic oxygen to carbon (O/C) ratios did not reveal a trend between maturity of CM and preg-robbing behavior, possibly due to low resolution of electron microprobe analysis. However, the atomic O/C ratios agree with other chemical analysis, indicating that the organic carbon is very mature, similar to or higher in grade than anthracite coal.

Jan 1, 1999

By J. F. Lupo

Leaching operations combine both metallurgical and hydraulic processes to extract metals from the ore heap. In the design of leaching operations, metallurgical tests and simple hydraulic tests are often conducted to define operational parameters such as leach cycle time, application rate, lift height, and effective leach area. While metallurgical constraints are often the primary focus on leach facility design, the hydraulic factors are also critical to the overall success of the operation. Some of the hydraulic factors that are known to impact solution flow through heaps include: • Ore physical and hydraulic properties, • Variation in ore properties under heap loading, • Ore mineralogy and its susceptibility to chemical and/or mechanical degradation, and • Heterogeneities within the heap. This paper presents a discussion on hydraulic factors that may impact the effectiveness of leaching operations. In addition, methods are presented which may be used to assess flow conditions within active and inactive heaps.

Jan 1, 2000

By M. A. Raza

Cable shovels are capital-expensive and primary production equipment in many surface mines. The forces acting on the shovel dipper vary as the dipper moves through the muck-pile. The variations in the forces cause stress loading of the components of shovel and dipper resulting in unplanned downtimes, reduced shovel efficiency, and high mining costs. A potential solution to the above problems is the deployment of an intelligent shovel excavation (ISE) technology, with real-time formation identification, recording, and knowledge transmission capabilities. This research advances the ISE technology by developing dynamic model of cable shovel dipper using Newton-Euler techniques. The model includes the dynamic cutting and dynamic weight forces acting on the dipper as it moves through the muck-pile.

Jan 1, 2011

Accurately estimating load distributions and ground responses around underground openings play a significant role in the safety of the operations in underground mines. Adequately designing pillars and other support measures relies highly on the accurate assessment of the loads that will be carried by them, as well as the load-bearing capacities of the supports. There are various methods that can be used to approximate mining-induced loads in stratified rock masses to be used in pillar design. The empirical methods are based on equations derived from large databases of various case studies. They are implemented in government-approved design tools and are widely used. There are also analytical and numerical techniques used for more detailed analysis of the induced loads. In this study, two different longwall mines with different panel width-to-depth ratios are analyzed using different methods. The empirical method used in the analysis is the square decay stress function that uses the abutment angle concept, implemented in pillar design software developed by the National Institute for Occupational Safety and Health (NIOSH). The first numerical method used in the analysis is a displacement-discontinuity (DD) variation of the boundaryelement method, LaModel, which utilizes the laminated overburden model (Heasley, 1998).

Jan 7, 2020

By Kazuo Magata, Hirohiko Fujita, Masazumi Tashiro, Yoshiaki Sato, Yoshio Shinoda

The Shinkansen of the Japanese National Railways (JNR) presently in operation between Tokyo and Hakata, approximately 1,000 km, was constructed at three stages: between Tokyo and Shin-Osaka opening in 1964, Shin-Osaka and Okayama in 1972 and Okayama and Hakata in 1975. Works on the extension of 400 km from Okayama to Hakata were launched in March 1970. As construction of the undersea Shin-Kanmon Tunnel on the extension was the toughest task, requiring many, many months, the work was undertaken earlier than any other works on the extension. It was brought to its completion in June 1974 at the cost of about 22, 000 million yen. The Shin-Kanmon Tunnel is the third undersea tunnel constructed to connect the main island of Honshu and Kyushu across the Kanmon Straits. (Table 1)

Jan 1, 1976

Because of complex geological environments, a number of coal reserves occur in inclined or dipping coal seams in certain parts of the world. Longwall top coal caving using split-level a singleentry panel system (SSPS) has been widely used for extracting such coal seams with large thicknesses (greater than 6 m) in China because SSPS can reduce or mitigate problems of coal outbursts, gate road deformations, overturning of shields, downhill sliding of shearer and armored face conveyor (AFC), and so forth, during mining of inclined coal seams. Depth of yield is the range of yield coal from the rib of the pillar to the boundaries where yield ends. It plays a significant role in maintaining the gate pillar stability. This paper presents a study on the stability of an unconventional water-obstruction gate pillar (UWGP) formed by SSPS to prevent water inrush in mining of an inclined thick coal seam in a coal mine in China. As the shape of this pillar is non-cuboidal, nonparallelepiped, a conventional empirical or analytical method is not applicable for studying its stability.

Jan 7, 2020

By Chester M. F. Peters

The opportunity to make a close study of the available geologic data existing along the line of the California Aqueduct crossing of the Garlock fault in the Tehachapi Mountains was brought about first by my involvement in the prebid examinations, and later with contractors' claim cases. The California Aqueduct crosses through the western end of the Tehachapi Mountains and cuts across the Garlock fault zone at a location about 9 miles east from its junction with the San Andreas fault zone. This is about 65 miles northwest of Los Angeles and 38 miles southeast of Bakersfield (Fig. 1) (1). This map was published after the tunnels were started and shows the corrected geology. At the crossing the fault has north and south branches which extend northeastward for about 22 miles before converging. In the vicinity immediately east of the tunnel line the north branch of the fault starts to converge toward the west. After crossing the line it passes under the upper plate of the apparent easterly extension of the Pastoria thrust fault, so the actual junction with the south branch is obscured. The aqueduct design called for the expected active slip zone of the north Garlock fault branch to be crossed by the 2,800 foot long Pastoria siphon, which connects with the north portal of Tehachapi Tunnel No. 3. The tunnel would extend through the western end of Genghus Ridge which lies between the north branch and the main south Garlock fault zone in Beartrap Canyon. Here again the

Jan 1, 1997

By F. F. Roberto

Many techniques that are used to characterize and monitor microbial populations associated with sulfide mineral bioleaching require the cultivation of the organisms on solid or liquid media. Chemolithotrophic species, such as Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans, or thermophilic chemolithotrophs, such as Acidianus brierleyi and Sulfolobus solfataricus can grow quite slowly, requiring weeks to complete efforts to identify and quantify these microbes associated with bioleach samples. Real-time PCR (polymerase chain reaction) assays in which DNA targets are amplified in the presence of fluorescent oligonucleotide primers, allowing the monitoring and quantification of the amplification reactions as they progress, provide a means of rapidly detecting the presence of microbial species of interest, and their relative abundance in a sample. This presentation will describe the design and use of such assays to monitor acidophilic microbes in the environment and in bioleaching operations. These assays provide results within 2-3 hours, and can detect less than 100 individual microbial cells.

Jan 1, 2009

By T. W. Beck

Drilling into coal mine roof strata to install roof bolts has the potential to release substantial quantities of respirable dust. Due to the proximity of drill holes to the breathing zone of roof bolting personnel, dusts escaping the holes and avoiding capture by the dust collection system pose a potential respiratory health risk. Controls are available to complement the typical dry vacuum collection system and minimize harmful exposures during the initial phase of drilling. This paper examines the use of a bit sleeve in combination with a dust hog-type bit to improve dust extraction during the critical initial phase of drilling. A twisted-body drill bit is also evaluated to determine the quantity of dust liberated by comparison to the dust hog-type bit. Based on these laboratory tests, the bit sleeve may reduce dust emissions by one-half during the initial phase of drilling before the drill bit is fully enclosed by the drill hole. Because collaring is responsible for the largest dust liberations, overall dust emissions can also be substantially reduced. The use of a twisted-body bit has minimal improvement on dust capture compared to the commonly used dust hog-type bit.

Feb 27, 2013

By M. D. Khattar

Problems discussed concern encountering of high temperatures [up to 66°C] and heavy flow of water [150 L.P.S] during the construction of the 10.15 MØH.R.T. for the 2500 MW Nathpa Jhakri Hydro Power Project in the Himalayas(India). Over a length of 2500 M progress of work got seriously affected resulting in excessive time for completion - two years [max. monthly progress achieved was 178 M [Heading]. Many innovative and simple steps were taken to complete the work in these inhospitable environs affecting working of both men and machines. Also it meant a review of the design of concrete lining. Other geological conditions affecting the progress are also described.

Jan 1, 1999

By Youngtak Ko, Wonnyon Kim

Korean contract Mn-nodule field in the NE equatorial Pacific is composed of seven sectors showing average water depths of 4,513 - 5,025 m. Of the various factors controlling the property of Mn-nodules, water depth has a potential linkage to chemical composition, shape and abundance of nodules. To clarify such a possibility, we review more than 20 years of research data in one of the northern sectors (hereafter KR1) where there is a marked contrast in water depth. High-resolution seabed mapping clearly separates a northern part from a deeper southern part, cutting across the middle of the KR1. In terms of nodule occurrence, manganese nodules in the deeper north are comparatively larger (2-4 cm) with rough surface (t-type) and discoidal shape (D-type), while those in the south are generally small (<2 cm) with smooth surface (s-type) and irregular shape (Itype). In addition, the nodules in the north have higher metal contents including Cu, Mn and Ni. Such connections of water depths to nodule occurrence and metal contents are commonly observed in the Korea licensed Pacific nodule fields. However, the relation between nodule abundance, size and water depth may be a different story. In KR1, nodule abundance and size are probably controlled by morphological features especially in the north. Seamounts in the north continuously provide rock fragments as new nuclei for the nodules. As a result, the nodules can not grow larger than 2 cm and show the shapes of newly formed nodules (i.e., smooth surface and irregular shapes). Such an interpretation is supported by anomalously high backscattered intensities in the side-scan sonar image map of the north, which possibly reflects a younger generation of magmatic activity.

Sep 1, 2014

By R. Abel, T. Wildeman, N. Heflin

A study was conducted to assess environmental effects of waste rock piles on water in the Russell Gulch area. Each pile was rated on physical characteristics of proximity to an ephemeral gulch, extensiveness of erosion features, size, presence of vegetation, and presence of a kill zone. Chemical assessments focused on three leachate tests performed on waste rock samples. Ratings were based on pH, conductivity, acidity, and analysis for 31 metals using inductively coupled plasma emission spectroscopy. The chemical and physical assessment of each site is used to make a rating of each pile on its overall potential to deliver contaminants.

Jan 1, 2004

By V. McLemore, A. Fakhimi, K. Donahue, D. Sweeney, V. Viterbo

In order to evaluate the relationships between weathering and durability and strength of rock samples from the Goathill North rock pile at the Molycorp Questa mine, NM, we conducted slake durability and point load tests. Slake durability index (ID2) values ranged from 84 to 98%. Point load strength index (Is50) averaged for all rock units ranged from 1.1 to 5.7 MPa. Results show a slight positive trend between ID2 and paste pH. Two populations of data are distinguishable when ID2 is plotted versus the percentages of chlorite, illite and internal friction angle. In general, Is50 values increase toward the interior of the rock pile. Preliminary conclusions indicate that the durability and strength of the rock pile material generally increase toward the interior of the rock pile. Pre-rock pile alteration and post-rock pile weathering history have affected the durability of the GHN rock pile samples.

Jan 1, 2007

The ventilation conditions at the underground coal mines are influenced; first: by the disturbances of the natural nature (barometric pressure, methane liberation, etc.), and second: by the disturbances caused by the production process. The major goal of this study was to determine the changes of the ventilation parameters, such as the flow, pressure and methane concentration around the longwall panel, particularly, along the longwall face due to the shearer operation (motion). It is well known from the practice, that the movement of the shearer influences the ventilation parameters around the longwall panel, including the gob area. Until now, these data were gathered in a single or multiple locations at the different time. However, only the simultaneous measurements of all of these values allow seeing the time dependent interrelationships between measured parameters. To be able to show these interrelationships, special experiments, described in this paper, were carried out by the author. These experiments were prepared and executed at the BUDRYK Coal Mine in Poland. During each experiment a simultaneous measurements and monitoring of the barometric pressure, air velocity and methane concentration at the different locations along the longwall face, were performed. The investigation was possible by using a special setup of instruments with a short sampling time, i.e., within 2 seconds. The monitoring of the absolute pressure was conducted by using the digital barometer µBar, developed by EMAG, based on the SETRA pressure transducer, model 470. The velocity of air was measured using the electronic vane-anemometers, developed by IMG-PAN. The methane concentrations were measured using methanometers as the part of the EMAG automatic gas monitoring system. The investigation data confirmed that disturbances due to the operation (motion) of the shearer at the longwall face have a local character. It could be also seen that a large diameter shearer (compared to the total cross-section area available for the air flow) is acting as the piston compressing the air (the overpressure) ahead of the shearer. This fact affects the methane mixing process and flow patterns in the vicinity.

Jan 1, 2009

By P. M. Prasad

Off-grade molybdenite concentrates, mainly derived from secondary sources as by-products of the processing of copper, uranium and tungsten ores, do not satisfy the purity requirements (percent MoS2) for the production of molybdenum bearing products. This investigation is a continuation of a successful effort to refine a low-grade molybdenite concentrate to prepare a high-grade MoS2 using a mixed acid (HF + HCl) leach procedure. Specifically, this investigation is concerned with an understanding of the separation chemistry underlying the removal of the oxide/silicate gangue and the base-metal sulfide associations present in the low-grade molybdenite by their selective dissolution in the two acids. Experiments were conducted on an off-grade concentrate containing 42.6% Mo. Results of the controlled dissolution tests indicate that both HCl and HF are suitable for the removal of the associated alumina and both work well for iron, nickel and copper. However, HF was found to be the most effective for dissolving silica/silicate and magnesia. An attempt was made to rank the leaching efficiencies of the acids used singly, sequentially or in a mixed mode. Scale-up (300 to 2,000 g) experiments were conducted to validate this approach. Excellent purification of the concentrate was possible by processing the off-grade concentrate with 10% HCl plus 15% HF at 363 K for 7.2 ks in open polypropylene reactors with internal stirring. These conditions leached practically all of the oxide and silicate gangue and 96% of the metallic impurities. Starting from the low-grade molybdenite concentrate (42.6% Mo; 71.1% MoS2) it was found feasible to obtain a refined product containing 97.8% MoS2, which is suitable for industrial use.

Jan 1, 2007

By Y. Nien Wang, Moe Amini, Heiner Sander, Max John

INTRODUCTION As the population increased along the coast route (California Route 1), and the people’s need to have guaranteed access increased, the landslides and related road closures began to have serious adverse economic impacts. Landslides were causing major long-term road closures about every 10 years on average. In 1983, ground movement at Devil’s Slide caused Highway 1 to be closed for an extended period of time which caused significant economic loss to the surrounding coastal communities. A number of options for bypassing the slide area were considered, and the Martini Creek inland bypass was selected for design. Subsequent litigation led to the creation of the Devil’s Slide Tunnel Study in 1996. The results of this study indicated that a tunnel alternative would be competitive with the inland bypass. The final decision was left to the citizens of San Mateo County, who approved the tunnel alternative in the November, 1996 election After completion of environmental studies and the processing of legal challenges, the final environmental document was finished in 2001. The preferred tunnel alternative was designated to proceed for final design and construction. PROJECT DESCRIPTION The Devil’s Slide Tunnels consists of a separated two-lane road, one lane in each direction, which passes through twin tunnels and over twin bridges and then connects with the existing non-separated, two-lane road at each end. The total length of the project is approximately 1900 meters consisting of four main project divisions, which are described below, going from south to north. 1.Operations and Maintenance Center (OMC) area, 2.Southern approach roadways to the South Portals (250 meters), including the South Rock Cut,

Jan 1, 2005